Organic dust toxicity (pulmonary mycotoxicosis) associated with silo unloading.

An acute febrile illness associated with unloading silos occurs more frequently than any other farm associated respiratory illness in mid state New York. This report describes 29 cases of organic dust toxic syndrome (also known as pulmonary mycotoxicosis) occurring in 24 men and one woman with a mean age of 29 years. In 16 instances more than one worker was exposed to the dust, and in 12 of these shared exposures more than one worker became ill. Patients presented 5.3 (SD 3.3) hours after inhalation of organic dust and mould with fever (79%), myalgia (76%), chest tightness (72%), cough (66%), and headache (59%). The mean temperature was 38.7 degrees C and the mean white blood cell count 13.2 X 10(9)/l. In contrast to patients with allergic alveolitis, nearly all these patients had normal breath sounds, chest radiographs, and arterial oxygen saturation. Tests for precipitating antibodies to farmer's lung disease antigens gave negative results in all 26 episodes in which they were done; of these, 10 had no evidence of precipitating antibodies to an aqueous extract of the silage associated with their own illness. Organic dust toxic syndrome appears to be a common and substantial respiratory hazard to young farm workers. Despite being frequently mis-diagnosed as farmer's lung, organic dust toxic syndrome is clearly a distinctly different disease process.